A liquid sealed engine mount for a motor vehicle is publicly known. A liquid chamber is partitioned by a partition member into a primary liquid chamber and a secondary liquid chamber. The primary liquid chamber is in communication through an orifice with the secondary liquid chamber. An insulator as a vibration isolating main body of a circular truncated cone shape faces into the primary liquid chamber. The insulator is elastically deformed by the vibration which allows the primary liquid chamber to be expanded and contracted, so that fluid resonance is created at the orifice thereby to provide the preferred dynamic characteristics of high damping and low dynamic spring.
The insulator of a circular truncated cone shape is formed in the shape of substantially a mountain along a mount axis (a central axis of the liquid sealed mount), and has an electing type and an inverted type according to projecting directions of a top of the mountain. The electing type is so formed that in the case where the vibration on the side of pressurizing the primary liquid chamber is a plus vibration (the vibration on the opposite side is a minus vibration), the top of the insulator is arranged to receive the plus vibration in the input direction of the plus vibration, while the inverted type is so formed that the top of the insulator is arranged in the same direction as the input direction of the plus vibration. Each of the electing type and the inverted type is publicly known.
This inverted type has the insulator of the truncated cone-shaped vibration isolating main body projecting into the primary liquid chamber in substantially a mountain shape. The characteristic of the inverted type is that since a piston size which is a projected area in the direction of the mount axis of the insulator becomes large, the liquid movement in response to the elastic deformation of the insulator is increased in the range of a low frequency (for example, 20 Hz or less), thereby allowing the fluid resonance (hereinafter, this fluid resonance is referred to as low frequency range resonance) to be efficiently performed whereby to improve the vibration isolating effect effectively.
Further, since a recess in substantially a V-shape in cross section is annularly formed between a periphery of the insulator and a peripheral wall of the primary liquid chamber, the fluid resonance peculiar to the inverted type occurs in an intermediate and high frequency ranges (for example, 100 Hz or more) when the liquid flows in the circumferential direction within the annular recess section (hereinafter, this fluid resonance is referred to as inverted type peculiar resonance).
By the way, it is known that since a noise is made in the intermediate and high frequency ranges due to a peak (a maximal value of dynamic spring curve) of antiresonance by this inverted type peculiar resonance, a resistor is provided in the annular recess section thereby to decrease the peak of the antiresonance and to change the resonance frequency. In the description hereunder, a minimum value of the dynamic spring curve is referred to as a bottom.
As such a resistor, there are known the type that a cylindrical separate member having a fin is inserted and fixed into an annular recess section (a patent reference 1), the type that a resistor such as rubber or the like is fixed by baking to a partition member (as an example, a patent reference 2), and the type that a resistor is integrally protruded into an annular recess section from a lining rubber provided on a wall of a liquid chamber (a patent reference 3).